Forces that Attract or Repel

Grade 3

��

��

OverviewIn Grade 3, students build on their initial awareness of forces aspushes or pulls (see Grade 2, Cluster 3: Position and Motion). Inthis cluster, the focus is on forces that act without directcontact: gravity, magnetism, and static electricity. Studentsdescribe evidence that shows that objects and living things on ornear Earth are affected by a force called gravity, enhancingtheir understanding of the nature of science. Through theirinvestigations, they determine that magnets have two poles andare surrounded by a magnetic field. They describe interactionsof like and unlike poles, and compare Earth to a giant magnet.In addition, they identify ways of producing electrostaticcharges using everyday materials. Students show how thestrength of magnetic and electrostatic forces varies underdifferent conditions. New understandings of gravity, magnetism,and static electricity are further refined as students identify andconstruct devices that use these forces.

Kindergarten to Grade 4 Science: A Foundation for Implementation

3. 34

SUGGESTIONS FOR INSTRUCTION

Students will...

PRESCRIBED LEARNING OUTCOMES

�� Observing Forces

Have students work in cooperative groups to explore howvarious objects move. Use objects such as toy cars, ball pointpens, balls, wagons, toboggans, vacuum cleaners, etc. Havestudents classify objects that move according to the grid below.

Ask the following question: “What are pushes and pulls?” If theterm “force” does not come up in the discussion, introduce it atthis time.

�� Gravity in Space

Have students view video clips showing astronauts in space andin spaceships. Use these images to initiate a discussion ongravity.

�� Finding Evidence of Gravity

Have students observe their environment to find evidence ofgravity. Example:

Ask students the following questions:• Why do things fall to the ground?• Why don’t we fly off/fall off the Earth?Ensure that a link is made to gravity as a pull and therefore atype of force, during discussions of gravity.

��

��

��

��

��

3-3-01 Use appropriate vocabularyrelated to their investigations offorces.

Include: force, attract, repel, gravity,magnet, magnetize, magnetism, northpole, south pole, magnetic field,compass, electrostatic charge, staticelectricity, electrostatic force.

GLO: C6, D4

3-3-02 Recognize that force is apush or pull and that attraction andrepulsion are types of pushes andpulls.

GLO: D4

�� Introduce, explain, use, and reinforce vocabulary throughoutthis cluster.

3-0-2a. Access information using a variety ofsources. Examples: children's magazines, localfarmers, CD-ROMs, Internet... (ELA 1.1.2,3.2.2; Math SP-I.1.2.3; TFS 2.1.1) GLO: C63-0-4f. Assume roles and share responsibilitiesas group members. (ELA 5.2.1) GLO: C7

3-0-5a. Make observations that are relevant to aspecific question. GLO: A1, A2, C2

3-3-03 Describe evidence showingthat objects and living things on ornear Earth are pulled toward it by aforce called gravity.

GLO: A2, D4

3-0-4e. Respond respectfully to the ideas andactions of others, and recognize their ideas andcontributions. (ELA 1.1.2, 5.2.2) GLO: C5, C7

3-0-4f. Assume roles and share responsibilitiesas group members. (ELA 5.2.1) GLO: C7

3. 35

SUGGESTIONS FOR ASSESSMENT

Grade 3, Cluster 3: Forces that Attract or Repel

TEACHER NOTES

Science Journal Entry: Gravity in SpaceHave students answer the following question in their sciencejournals: Gravity is invisible. What evidence do we have thatgravity is acting on objects on the Earth? Give at least sixexamples.

Look for the following examples:

� objects falling

� water running downhill

� a ball thrown into the air comes back down again

Caution: Ensure that students areaware that a magnet should not beheld near the following technologicaldevices: television, VCR, microwaveoven, computer, radio, loudspeakers,credit cards, wind-up watches,computer discs, audiocassettes, taperecorders, telephones, answeringmachines, and videotapes. Magnetsdisrupt the electronic components.This results in permanent damage.

The space around a large mass, suchas the Earth, is called a gravitationalfield. It’s the area where the force ofgravity acts or can be felt.


3. 36


Students will...


�� Magnetic or Not?

Provide students with a variety of objects. Have students predictwhich objects will be attracted to the magnet. Include metalssuch as copper, brass, and aluminum which are not magnetic.Have students test to determine the accuracy of their predictions.

Provide students with an opportunity to review and reflect on theresults. Help guide students’ reflections by asking the followingquestion:

How are the materials attracted by magnets alike?

�� Investigation — Creating Temporary Magnets

Provide students with bar magnets, paper clips, and iron nails.Tell students that temporary magnets can be made by strokingthe metallic object with a magnet. Have students test todetermine whether they can magnetize a paper clip and an ironnail. Following the investigation, ask students the followingquestions to reflect on the process:• Were you able to magnetize the paper clip and the nail?• What procedure did you try?• What procedure worked best?• What did you notice about the strength of the magnetic

attraction with the paper clip and the nail?Have students try to magnetize other materials and report theirfindings to the class.

�� Magnetic Neighbours

Have students use a permanent magnet and a non-magneticmetallic object, such as a paper clip to determine whether anobject can become magnetized from being near a magnet.

��

��

��

3-3-04 Predict and test to identifymaterials that are attracted bymagnets and those that can bemagnetized.

GLO: C2,, C5 D3

3-3-05 Investigate to determine howto magnetize a given object.

Include: contact with anothermagnet, proximity to a magnet.

GLO: C2, D4

3-0-1b. Make predictions based on observedpatterns, collected data, or data provided fromother sources. (ELA 1.1.1; Math SP-IV.2.3) GLO:A1, C2

3-0-3d. Brainstorm, in small groups, possiblesolutions to a practical problem, and reachconsensus on which solution to implement.GLO: C3, C7

3-0-4a. Carry out a plan, and describe the stepsfollowed. (Math SP-V.2.3) GLO: C2

3-0-4g. Verbalize questions, ideas, andintentions during classroom-learningexperiences. GLO: C6

3-0-7e. Communicate results and conclusions ina variety of ways. Examples: point-form lists,sentences, simple diagrams, charts,demonstrations... (ELA 2.3.5, 3.3.2, 4.1.3; MathSP-III.2.3; TFS 2.1.4) GLO: C6

3. 37

Observation Checklist: Magnetic or Not?The student

� uses safe and appropriate procedures with the magnets

� records observations accurately

� predicts which objects would be attracted to a magnet

� tests to confirm predictions

� participates in the development of a plan for magnetizing anobject

� follows the plan

� asks relevant questions

� explains ideas to others

� represents findings using a variety of methods

� demonstrates proper care of magnets

TEACHER NOTES SUGGESTIONS FOR ASSESSMENT


There are three different kinds ofmagnets: natural, temporary, andpermanent.

Natural magnets are rocks with a lotof iron in them and are magneticwhen found in the ground (lodestone).

Temporary magnets can be madefrom steel; however, they are weakand last only a short time.

Permanent magnets are made fromhard iron (iron and other materials).

Magnets need to be stored properly inorder to ensure that they stay stronglymagnetized.They should be storedwith opposite poles together.

If magnets do become de-magnetized,they can be re-magnetized. Highschool science labs often have thedevice with which to effect this. Ifnot, it can be purchased from ascience supply store.

attract - to pull toward or hold inplace

repel - to push away or force apart

magnet - a material that can attract apiece of iron

ceramic magnet - magnets madefrom a powdered iron oxide calledferrite, are strong and versatile

When a magnetic metal is attracted toa permanent magnet, it becomes amagnet, too. It can attract otherobjects but only while it is touching apermanent magnet. This is calledinduced magnetism.


3. 38


Students will...


�� Exploring Magnetic Poles

Part 1) Provide small groups of students with two bar magnetsthat have their poles labelled. (This can be done with maskingtape.)

Have students explore to determine what happens when likepoles are placed together and when unlike poles are placedtogether. Have each group present its findings. If the terms“repel” and “attract” do not come up in the discussion, theyshould be introduced at this time. Students should recognize thatbecause magnetism either pushes or pulls, it is a force.

Part 2) Provide each group with a labelled bar magnet andmagnets that do not have labelled poles. Have studentsdetermine the location of the north and south poles on theunlabelled magnets and explain the procedure used.

�� Investigating Magnetic Fields

Provide small groups of students with cardboard, iron filings ina shaker, and different types and shapes of magnets (bar,horseshoe, fridge). Have students place the magnet under thecardboard and then gently sprinkle the iron filings on top. Havestudents draw what they observe. Ask students the followingquestions:

• What did the magnets have in common?

• What do you call the pattern made by the iron filings? (magnetic field)

Have students explore to answer the following questions:

• How does the magnetic field change when you put north and south poles together?

• North and north poles together?

• South and south poles together?

3-3-06 Investigate to determine thelocation of poles on a magnet, andthe shape of the magnetic fieldaround a magnet.

GLO: A1, C2, D4

3-3-07 Demonstrate that oppositepoles attract and like poles repel.

GLO: C2, D4

3-0-4h. Follow given safety procedures and rules,and explain why they are needed. GLO: C1


3-0-9a. Listen to and consider differing opinions.(ELA 5.2.3) GLO: C5, C7

3. 39

Interview: MagnetsBefore the interview, gather a labelled bar magnet and an unlabelledbar magnet. Ask students the following questions:

1. Explain what will happen when the poles of two bar magnets areput together in the following ways:

North pole to south pole? (��)

North pole to north pole? ��

South pole to south pole? ��

2. Draw the magnetic field for this bar magnet. (See Teacher Notes.)

3. Explain how you would find the poles on a magnet that is notlabelled. (Use the labelled bar magnet to find the poles on theunlabelled magnet.)

4. How should you care for magnets?

� don’t drop them

� store them with unlike poles together

� keep them away from electronic equipment

� other

N S



The space around a magnet is calledthe magnetic field. It’s the areawhere the force of a magnet acts orcan be felt.

Magnetic Fields

WW

Opposite poles have a powerfulattraction.

Two like poles (north and north, orsouth and south) push against orrepel each other strongly.

Where the lines are closest, themagnetic field is strongest.


3. 40


Students will...


�� Earth Magnetic Simulation

Stick a bar magnet through the centre of an orange but makesure the ends are visible to the students. Demonstrate with acompass that the needle will point to the magnet’s north whenplaced near the orange. If you go outside with your compass, theneedle will point to the Earth’s magnetic north.

�� Making Floating Compasses

Have the students work in small groups to make floatingcompasses. Have students gather needed materials including:objects that float such as a leaf, piece of styrofoam, cork orpiece of plastic; a magnet; a non-metallic dish of water; and alarge sewing needle. Have students magnetize the needle withthe magnet and test it to ensure it is magnetized. Students thenplace the floating device in the water and set the needle on it.The floating device should turn until the needle pointsnorth/south. Use a compass to test if the needle is pointing north.Turn the floating needle away from the north and observe whathappens. Use the following questions to guide the discussion:

• What causes the needle to point to the north magnetic pole?

• Why couldn’t you use a steel bowl to hold the water?

S

N

WE

S

N

3-3-08 Explain why Earth can becompared to a giant magnet.

Include: Earth has a magnetic fieldwith poles adjacent to thegeographic poles.

GLO: D4, E1, E2

3-3-09 Demonstrate and explain howa compass operates by magnetism.

Include: Earth’s magnetic poleattracts the magnetic needle of acompass.

GLO: B1, D4


3-0-5a. Make observations that are relevant to aspecific question. GLO: A1, A2, C2

3-0-5b. Use tools to observe, measure, andconstruct. Include: ruler, metre stick, panbalance, magnifying glass, bathroom scale,thermometer, magnet. (Math SS-I.1.3, SS-III.1.3,SS-IV.1.3, SS-VII.4.3) GLO: C2, C3, C5

3-0-9c. Take the time to repeat a measurementor observation for greater precision or detail.GLO: C5

(continued)

3. 41

Performance Task: Finding Poles With a CompassStudent directions: You have been asked to determine the poles onan unmarked magnet using only a magnetic compass. Develop awritten plan. Demonstrate how your plan works, using theunmarked magnet and a compass.

Scoring Rubric

Scale Plan Follows Plan Identifies Poles

4 complete and well organized

3 clear and complete

2 complete but unclear

1 unclear, may contain misconceptions

yes yes

yes yes

perhapsperhapsno

yes, with assistance

The centre, or inner core of the Earth ismade up of iron and nickel. This innercore flows and rotates faster than theouter core and it is believed that thismovement creates the Earth’smagnetic field.

As a magnet, the Earth has north andsouth magnetic poles. Scientists havefound that the location of the poles isshifting over time. Every few hundredthousand years, the magnetic polesactually reverse themselves, butscientists don’t know why.

The Earth also has another set of poles,the geographic North and South Poles.These poles are at the axis upon whichthe Earth turns. The magnetic northpole and the geographic North Poleare approximately 1600 kilometresapart. People navigating using acompass and geographic maps mustmake adjustments for the differences inlocation between the two north poles ofthe Earth.

Ensure that the discussion of the Earthas a magnet does not become confusedwith discussions about gravity.




3. 42


Students will...


�� Finding Poles With a Compass

Have students use a magnetic compass and a bar magnet toobserve the effects of moving the compass to different locationsaround the bar magnet. Students should record their observationsin their science journals.

Ask students: “How can you use this information to locate thepoles on an unmarked magnet?” Have students test to determineif their plan will work.

�� Magnets Affect Electronic Equipment

Part 1) Make a tape and play it for the students. Place a magnetclose to the tape and play the tape again. Discuss the resultsusing the following questions:

• What happened to the tape?

• Why did this happen?

Part 2) Show students a sensor pad warning label.

Ask the students what other objects might be affected bymagnets and record the information on a class chart. Havestudents add to the chart as study of the cluster ensues. For thislearning outcome, any research that takes place should beundertaken by using books, CD-ROMs, the Internet, etc., andnot by exploring with magnets.

WARNING: Magneticfield. Do not place credit

cards near this pad

N S

3-3-10 Describe potentially harmfuleffects of magnets on magnetizedmaterials.

Examples: computers, videotapes,credit cards...

GLO: B1, C1, D4

3-0-2a. Access information using a variety ofsources. Examples: children’s magazines, localfarmers, CD-ROMs, Internet... (ELA 1.1.2, 3.2.2;Math SP-I.1.2.3; TFS 2.1.1) GLO: C6

3-0-2b. Review information to determine itsusefulness to research needs. (ELA 3.2.3,3.3.3) GLO: C6, C8


compasslocations

3. 43



Caution: Ensure magnets remain inthe classroom and that students areaware of the potential danger theypose to magnetized devices such ascomputers.


3. 44


Students will...


�� Exploring Electrostatic Charges

Provide each student with an inflated balloon. Have them rub theballoon against their hair and observe what happens. Ask thestudents why they think this is happening. If the concept of staticelectricity or electrostatic charges does not occur in thediscussion, it should be introduced at this time. Have studentswork with a partner or in small groups to find other ways ofproducing electrostatic charges. Provide materials such as: wool,cotton, polyester, paper, plastic, silk, a carpet sample, andcharged inflated balloons.

�� Stick to It

Have students select the three materials that they feel work bestto create electrostatic charges. Have students investigate to see ifincreasing the number of times the balloon is rubbed increasesthe time that it will stick to the wall. Have students use a chart torecord results.

��

Math link: graph the results. Have students share the results with other pairs of students.Provide time for students to think about their results. Discussfindings using the following questions:

• Does the balloon stick longer when rubbed with certain materials?

• Do more rubs with the same material increase the sticking time?

• Are the results from your group the same as results from other groups? Why or why not?

��

!��

"#��

3-3-11 Describe and demonstrateways to use everyday materials toproduce electrostatic charges.

Examples: rubbing feet on carpet,brushing hair, rubbing a balloon onclothes...

GLO: D4

3-0-3b. Identify, with the class, variables thathave an impact on an investigation. GLO: A1,A2, C2, C7

3-0-7a. Draw a simple conclusion based on theirobservations. GLO: A1, A2, C2

3-0-7b. Explain why conclusions related toclassroom experiments should be based onmultiple trials or classroom data rather than onan individual result. GLO: A1, A2, C2

3-0-8a. Recognize that valid experimentsnormally have reproducible results, which mayvary slightly. GLO: A1, A2, C2

3-0-8b. Recognize that scientists developexplanations from observations and what theyalready know about the world, and that goodexplanations are based on evidence. GLO: A1,A2, C2

3. 45

Science Journal Entry: Electrostatic ChargesStudent directions: Describe, using words and diagrams, how toproduce a static charge.

Look for

� rubbing two materials together

� rubbing long enough to create a charge (more than just touching two materials together)



The atoms of all matter are made upof electrons (negative charges),protons (positive charges), andneutrons (no charge). Protons andneutrons are found in the nucleus.Electrons whirl around the nucleus.Some have the ability to move fromone atom to another. There are anequal number of protons andelectrons in each atom. As a result,atoms are ordinarily electricallyneutral.

When a balloon is rubbed on a cloth,electrons are transferred from thecloth to the balloon. The balloonbecomes negatively charged. If aballoon comes in contact with aneutral wall/hair, etc., it pushes awayelectrons from that section of thewall/hair. This results in a positivecharge on that part of the wall.Because opposites attract, theballoon will stick to the wall or willmake the hair stick to the balloontemporarily. After a while thenegative electrons pass from theballoon to the wall and also into theair. Then the balloon/hair falls.

Caution: Do not allow students toput balloons on the computers.Remind them that computers shouldalways be grounded.


3. 46


Students will...


�� Electrostatic Interactions

Provide small groups of students with two inflated balloons and alength of thread or string for each. Have students tie a piece ofthread on the end of each balloon and hold the balloons by theirthreads so that they are about 5 cm apart. Students observe whathappens. Have students charge one balloon and then hold theballoons together. Have students charge both balloons and then holdthem together. Use the following questions to guide the discussion:

• What happens when uncharged materials are placed together? (Nothing.)

• What happens to uncharged material when a statically charged material is placed near it? (It is attracted to the charged material.)

• What happens when two statically charged materials come together? (They repel or attract one another.)

�� Statically Charged Materials

Provide a piece of plastic wrap and paper towel for each student.Have students charge the plastic wrap by placing it on a flatsurface and rubbing it with the paper towel. The students lift theplastic wrap by one corner and observe what happens and recordtheir observations. Then have students straighten out the plasticwrap and rub it again to recharge. Have them pick it up in themidpoint of the opposite side and observe and record whathappens.

�� Demonstration: Moving Water

Charge a comb by rubbing it on a piece of wool. Hold the combnear slowly running tap water. Have students observe how thewater reacts to the statically charged comb. (The water willsurprisingly appear to be drawn to the comb.) Discuss the results.

3-3-12 Investigate to determine howelectrostatically charged materialsinteract with each other and withuncharged materials.

Include: charged materials attract orrepel each other, charged materialsattract uncharged materials.

GLO: A2, C2, D4


3-0-3c. Create, with the class, a plan to answera given question. (ELA 3.1.4) GLO: C2, C7

3-0-5e. Record observations in a variety ofways. Examples: point-form notes, sentences,simple diagrams, charts... (ELA 3.2.1, 3.3.2,4.1.3; Math SP-II.2.1, SP-V.2.3) GLO: C2, C6

3-0-7a. Draw a simple conclusion based on theirobservations. GLO: A1, A2, C2

3. 47

Paper and Pencil Task: Electrostatic InteractionsUsing words and diagrams, have students answer the followingquestions:

• What happens when uncharged materials are placed together?

• What happens when uncharged materials come in contact with astatically charged material?

• What happens when two statically charged materials cometogether?




3. 48

�� Staying Safe

Have students work in small groups to brainstorm and list whatthey might do to be safe during a lightning storm. Discuss withstudents the recommended safety precautions one should take ifcaught outside during a storm such as: crouch down, spread out,avoid trees, telephone poles, and fences, and do not touch metalobjects, e.g., bicycle, fishing rod, etc.

�� Safety Posters

Discuss with students home safety procedures to follow during astorm. Suggestions could include: avoid using the telephoneunless there is an emergency, no standing near open doors orwindows, and stay away from electrical appliances. Havestudents use these ideas to create safety posters.

�� Avoid the Static!

Organize a discussion regarding the safety procedures to be usedin order to avoid static electricity at school. Focus on the care ofelectronic equipment and the concern for personal safety.Students may suggest such things as grounding yourself beforeusing the computer, avoiding shuffling feet on carpets, etc.


Students will...


3-3-13 Identify ways in whichproblems associated with staticelectricity can be avoided oreliminated.

Examples: staying indoors whenthere is a lightning storm, groundingyourself before using computers,avoiding shuffling your feet oncarpets...

GLO: B1, C1, D4

3-0-4e. Respond respectfully to the ideas andactions of others, and recognize their ideas andcontributions. (ELA 1.1.2, 5.2.2) GLO: C5, C7


3. 49



Lightning is caused by staticelectricity. Sparks jump between twoareas of opposite and built-upelectrical charges. This can occur fromone part of a cloud to another or froma cloud to the ground. In the latter,there is a bolt from the cloud to theground and a return bolt, upward fromthe ground. These two strokes appearas one lightning bolt and they takeplace in less than a second. Manitobaexperiences intense summerthunderstorms and each yearManitobans are killed or seriouslyinjured by lightning strikes.


3. 50

�� Forces Over Distances

Part 1: MagnetsHave students work in pairs to determine if increasing thedistance between a permanent magnet and an object has anyeffect on the strength of the magnetic force. Have students use apermanent magnet and a collection of paper clips. Students willgradually increase the distance between the magnet and thepaper clips. They may record observations on a chart such as thefollowing

Math Connection: Have students record their observations on agraph.

Part 2: ElectrostaticsHave students develop and test a plan for examining the effectsof increased distance on electrostatic forces. Have studentsreport the results to the class. Example: Use a charged balloon topick up small pieces of paper (small, circular scraps from a holepuncher).

�� Forces Through and Through

Part 1: MagnetsProvide partners with a strong magnet, paper clips, and a varietyof materials such as cardboard, paper of various thicknesses,fabric, glass, tinfoil, plastic, wooden rulers, etc. Have studentspredict the effect of placing different materials between themagnet and the paper clips. Students then test to determine iftheir prediction was accurate, and then record their findings on achart such as the one below.

Give each pair of students a clear glass of water with a paperclip in the water. Have students try to remove the paper clipusing the magnet on the outside of the glass. Partners share theirresults with the class.

��

�� $�� $��

�� %%%%%%%%%%%%%%%% %%%%%%%%%%%

�� !� ��"��"��

"�� %%%%%%%%%%%%%%%%%%%%%%%%%%%%

&�� %%%%%%%%%%%%%%%%%%%%%%%%%%%%

'�� %%%%%%%%%%%%%%%%%%%%%%%%%%%%


Students will...


3-3-14 Investigate to determine thechange in magnetic and electrostaticforces at different distances.

GLO: C2, D4

3-0-3a. Brainstorm, with the class, one or moremethods of finding the answer to a givenquestion and reach consensus on which methodto implement. GLO: C2, C7

3-0-3b. Identify, with the class, variables thathave an impact on an investigation. GLO: A1,A2, C2, C7

3-0-3c. Create, with the class, a plan to answera given question. (ELA 3.1.4) GLO: C2, C7


3-0-5e. Record observations in a variety ofways. Examples: point-form notes, sentences,simple diagrams, charts... (ELA 3.2.1, 3.3.2,4.1.3; Math SP-II.2.1, SP-V.2.3) GLO: C2, C6

3-0-6a. Display data using more than one way torepresent the same data. (Math SP-III.2.3)

GLO: C2, C6

3-0-6b. Discuss data and generate newquestions from displayed data. (Math SP-IV.1.2)GLO: A1, A2, C2, C5

3-3-15 Predict and test to determinethe effect of placing materialsbetween a magnet and an attractedobject and between charged objects.

Examples: different thicknesses ofpaper, glass, water, metal...

GLO: C2, C5, D4

3-0-1a. Ask questions that lead to investigationsof living things, objects, and events in the localenvironment. (ELA 1.2.4) GLO: A1, C2, C5


3-0-4g. Verbalize questions, ideas, andintentions during classroom-learningexperiences. GLO: C6

3-0-9b. Express enjoyment when sharing anddiscussing science-related experiences fromdaily life. (ELA 4.4.3) GLO: C5

(continued)

3. 51

Observation Checklist: Forces Over DistancesThe student

� makes an organized list to record findings

� makes logical predictions based on previous observations

� uses safe and appropriate procedures

� works cooperatively and shared materials

� records predictions and observations accurately

� communicates results with others

� notices patterns forming in test results

� provides insight into the reaction of objects at different distances

� returns materials and tools to appropriate location

Self-Reflection: Forces Through and Through1. I liked ______________________________________________.

2. I had a problem with __________________________________.

3. If I did this investigation again I would ___________________.

4. I learned ____________________________________________.

5. I would like to learn more about ________________________.

Have students use Blackline Master 2:Scientific Inquiry Recording Sheet:Grades 3 and 4.




3. 52

Part 2: Electrostatic ForcesHave students determine the effect of placing materials betweencharged objects using a procedure similar to the one above formagnets. Ask students the following questions:

• What effect does the addition of a material between the force and the attracted object have on the force itself?

• Why did some students get different results with the same materials?

• How did your results compare with your predictions?

�� Reflection — Forces that Can Move without Touching

Have students use their science journals to list or drawexplorations they have undertaken showing how forces can pushor pull objects causing them to move without directly touchingthem (all magnetic and electrostatic explorations). For contrast,remind students of some of the learning experiences from Grade3, Cluster 2: Position and Motion, in which they caused objectsto move using direct pushes and pulls.

�� Observing the Environment: Find the Force

Have students explore the school environment to find uses ofgravitational, magnetic, or electrostatic forces (e.g., fridge door,cupboard doors, balance scales, dust mops, etc.). Have studentsrecord their findings. Challenge students to add to their lists withexamples from home.


Students will...


3-3-16 Recognize that gravitational,magnetic, and electrostatic forcescan move certain objects withouttouching them directly.

GLO: D4

3-3-17 Distinguish between motionthat is caused without contact andthat which is caused by contact.GLO: D4


3-0-7d. Examine how new experiences, ideas,and information connect to prior knowledge andexperiences, and record these connections.(ELA 1.2.1, 2.1.2, 3.3.3) GLO: A2, C6

3-3-18 Identify devices that usegravitational, magnetic, orelectrostatic forces.

Examples: balances, magneticcupboard latches, dust mops...GLO: B1, D4

3. 53

Self-Assessment: Creating Electrostatic Forces(Answer Yes or No)

1. I followed written and oral directions during the investigation.

2. I worked in an organized way.

3. I kept trying even when I was not successful.

4. I talked about my discoveries with others.

During this investigation I learned _________________________

_____________________________________________________.




3. 54

�� Design Project: Construct a Toy

Sample design scenario: A local toy manufacturer is holding adesign competition. In order to enter the contest you must designand construct a game or toy that uses gravitational, magnetic, orelectrostatic forces. You must also prepare a presentation toshow your product to the judges. Examples of toys or gamescould include the following:

• magnetic fishing game

• magnetic maze

• ring toss (uses gravity)

• gameboard for “Tic-Tac-Toe” that sticks to the fridge, awindow, etc.

• paper jumping beans

To make paper jumping beans, use coloured construction orbond paper, and cut out small bean shapes. Place these in a cardbox with a clear plastic lid. Rub the lid with a cloth to make thebeans jump and stick to the lid. Tap the lid to make the beansdrop.


Students will...


3-3-19 Use the design process toconstruct a game, toy, or usefuldevice that uses gravitational,magnetic, or electrostatic forces.

GLO: C3, C5

3-0-1c. Identify practical problems to solve in thelocal environment. GLO: C3

3-0-3d. Brainstorm, in small groups, possiblesolutions to a practical problem, and reachconsensus on which solution to implement.GLO: C3, C7

3-0-3e. Create, in small groups, a written plan tosolve a problem or meet a need. Include:identify steps to follow, prepare a simplediagram. (ELA 1.2.3) GLO: C3, C7

3-0-3f. Develop, in small groups, limited criteriato evaluate an object or device based on itsfunction and aesthetics. GLO: C3, C7

3-0-4b. Construct an object or device to solve aproblem or meet a need. GLO: C3

3-0-4c. Test an object or device with respect topre-determined criteria. GLO: C3, C5

3-0-4d. Identify and make improvements to anobject or device, and explain the rationale for thechanges. GLO: C3

3-0-5b. Use tools to observe, measure, andconstruct. Include: ruler, metre stick, panbalance, magnifying glass, bathroom scale,thermometer, magnet. (Math SS-I.1.3, SS-III.1.3,SS-IV.1.3, SS-VII.4.3) GLO: C2, C3, C5

3-0-7c. Identify new problems that arise.GLO: C3

3-0-8c. Recognize that designing a solution to asimple problem may have considerations, suchas cost, materials, time, and space. GLO: B2, C3

3. 55

Design Process Checklist: Construct a ToyThe student

� understands the problem

� actively participates in small-group brainstorming

� includes written list of steps to follow

� includes simple diagram

� contributes to the development of design criteria

� constructs the game or toy

� tests the game or toy based on given criteria

� identifies improvements to be made

� makes improvements

� works cooperatively

� shares group responsibilities

Peer Assessment of Design PresentationYes or No?

1. The speaker spoke so all could hear.

2. The speaker used visual aids or props.

3. The speaker clearly explained how the game or toy worked.

4. The speaker made me want to buy the toy or game.

Recommendations: _____________________________________

_____________________________________________________

_____________________________________________________

_____________________________________________________.

Have students use Blackline Master 4:Design Process Recording Sheet:Grades 3 and 4.




3. 56

NOTES

Documents

Forces that Attract or Repel